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AC/DC Module

AC/DC Module

Software for Computational Electromagnetics Modeling

Transient model of a single phase E-core transformer that is described by a nonlinear B-H curve in the core. The graph shows the electromagnetic field and current in the primary and secondary windings.

The AC/DC Module is used for simulating electric, magnetic, and electromagnetic fields in static and low-frequency applications. Typical applications include capacitors, inductors, insulators, coils, motors, actuators, and sensors, with dedicated tools for extracting parameters such as resistance, capacitance, inductance, impedance, force, and torque.

Materials and constitutive relations are defined in terms of permittivity, permeability, conductivity, and remanent fields. Material properties are allowed to be spatially varying, time-dependent, anisotropic, and have losses. Both electric and magnetic media can include nonlinearities, such as B-H curves, or even be described by implicitly given equations.

Boundary Conditions and Infinite Elements

The AC/DC Module grants you access to a set of essential boundary conditions such as electric and magnetic potential, electric and magnetic insulation, zero charge, and field and current values as well. In addition, a range of advanced boundary conditions are included, such as terminal conditions for connection with SPICE circuits, floating potentials, conditions for symmetry and periodicity, surface impedance, surface currents, distributed resistance, capacitance, impedance, and contact resistance. For modeling unbounded or large modeling domains, infinite elements are available for both electric and magnetic fields. When an infinite element layer is added to the outside of a finite-sized modeling domain, the field equations are automatically scaled. This makes it possible to represent an infinite domain with a finite-sized model and avoids artificial truncation effects from the model boundaries.

Additional images:

PERMANENT MAGNETS: This model presents the static-field modeling of an outward-flux-focusing magnetic rotor using permanent magnets. This magnetic rotor is also known as a Halbach rotor. The use of permanent magnets in rotatory devices like motors, generators, and magnetic gears is becoming more popular due to their non-contact, frictionless operation. This model illustrates how to calculate the magnetic field of a 4-pole pair rotor in 3D by modeling only a single pole of the rotor, using symmetry.

ECAD IMPORT: The AC/DC Module is used for capacitance and inductance extraction for a planar transformer model imported as an ECAD file. This type of device is used in power supplies and DC/DC converters where a slim high-power design is crucial. The entire layout, including the footprint of the transformer ferrite core, is imported from an ODB++(X) file. The ECAD Import Module is used to read the layout and automatically create a 3D geometry model of the Printed Circuit Board (PCB) and the ferrite core.

SEMICONDUCTOR MANUFACTURING: A susceptor of graphite is heated through induction. The model shows the temperature distribution inside the susceptor and on the quartz tube.

MEDICAL TECHNOLOGY: Simulation of the electromagnetic field in a high-voltage generator in an X-ray device. Model courtesy of Comet AG, Switzerland.

MASS SPECTROMETRY: The AC/DC Module in concert with the Particle Tracing Module. The visualization shows the trajectory of ions in a quadrupole mass spectrometer with a specific charge-to-mass ratio.

Combine Circuits and Layouts with 2D and 3D Simulations

When considering your electrical components as part of a larger system, the AC/DC Module provides an interface with SPICE circuit lists where you choose circuit elements for further modeling. More complex system models can be exploited using circuit-based modeling while maintaining links to full field models for key devices in the circuit, allowing for design innovation and optimization on both levels. Electronic layouts can be brought in for analysis with the AC/DC Module via the ECAD Import Module. Simulation of such layouts is not limited to electromagnetics.

Connect with CAD, MATLAB®, and Excel®

In order to make it easy for you to analyze electromagnetic properties of mechanical CAD models, COMSOL offers the ECAD Import Module, the CAD Import Module, and LiveLink™ products for leading CAD systems as part of our product suite. The LiveLink products make it possible to keep the parametric CAD model intact in its native environment but still control the geometric dimensions from within COMSOL Multiphysics®, as well as produce simultaneous parametric sweeps over several model parameters. For repetitive modeling tasks, LiveLink™for MATLAB® for allow you to drive COMSOL® simulations with MATLAB® scripts or functions. Any operation available in the COMSOL Desktop® can alternatively be accessed through MATLAB commands. You can also blend COMSOL commands in the MATLAB environment with your existing MATLAB code. For electromagnetic simulations operated from spreadsheets, LiveLink™for Excel® offers a convenient alternative to modeling from the COMSOL Desktop with synchronization of spreadsheet data with parameters defined in the COMSOL environment.

Nonlinear Magnetic Materials Database

A database of 165 ferromagnetic and ferrimagnetic materials is included in the AC/DC Module. The database contains BH-curves and HB-curves enabling the material properties to be used in the magnetic fields formulations. The curve data is densely sampled, and has been processed to eliminate hysteresis effects. Outside of the range of experimental data, linear extrapolation is used for maximal numerical stability.

Take Multiphysics into Consideration in Your Designs

Although devices may be principally characterized by electromagnetics, they are also influenced by other types of physics. Thermal effects, for instance, can change a material’s electrical properties, while electromechanical deflections and vibrations in generators need to be fully understood during any design process. The AC/DC Module, being comprehensively integrated in the COMSOL environment, allows for a wide range of physical effects to influence the virtual model.

Electromagnetic Shells

For very thin structures, the AC/DC Module provides a range of specialized formulations for efficient electromagnetic simulations where the thickness of the structures does not need to be represented as a physical thickness in the geometry model but can instead be represented with a shell. Such thin shell formulations are available for direct currents, electrostatics, magnetostatics, and induction simulations, and is particularly important for electromagnetic shielding within electromagnetic compatibility (EMC) and interference (EMI) applications.

Consistent Workflow for Electromagnetics Modeling

The module's straightforward workflow is described by the following steps: define the geometry, select materials, select a suitable AC/DC interface, define boundary and initial conditions, automatically create the finite element mesh, solve, and visualize the results. All these steps are accessed from the COMSOL Desktop®. AC/DC Module simulations can be connected with every COMSOL product in just about any way imaginable by a suite of preset multiphysics couplings or via user-defined couplings. A typical preset coupling is one between the AC/DC Module and the Particle Tracing Module where electric or magnetic fields affect charged particles that can be assigned to either have mass or be massless. The Optimization Module can be combined with the AC/DC Module for optimization with respect to voltage and current excitation, material properties, geometric dimensions, and more.

Flexible and Robust

The AC/DC Module includes stationary and dynamic electric and magnetic fields, both in 2D and 3D. Under the hood, the AC/DC Module formulates and solves Maxwell’s equations together with material properties and boundary conditions. The equations are solved using the finite element method with numerically stable edge element discretization in concert with state-of-the-art solvers. The different formulations admit static, frequency-domain, and time-domain simulations. Results are presented in the graphics window through preset plots of electric and magnetic fields, currents and voltages, or as expressions of the physical quantities that you can define freely, as well as derived tabulated quantities.

Supported File Formats

File Format

Extension

Import

Export

SPICE Circuit Netlist

.cir

Yes

No

Touchstone

.s2p, .s3p, .s4p, ...

No

Yes

Modeling Computational Electromagnetics with the AC/DC Module

With COMSOL Multiphysics and the AC/DC Module you can model static and low-frequency computational electromagnetics. By simulating electric, magnetic, and electromagnetic fields in static and transient applications, you can virtually design and analyze capacitors, inductors, insulators, coils, motors, sensors, and more. Additionally, understanding how your device or system is affected by physics other than electromagnetics is crucial to the integrity of your designs. Therefore, as with all COMSOL products, the interfaces within the AC/DC Module can be combined with any other module to account for thermal, structural, and fluid interactions in your system.

With COMSOL Multiphysics and the AC/DC Module you can model static and low-frequency computational electromagnetics. By simulating electric, magnetic, and electromagnetic fields in static and transient applications, you can virtually design and analyze capacitors, inductors, insulators, coils, motors, sensors, and more. Additionally, understanding how your device or system is affected by physics other than electromagnetics is crucial to the integrity of your designs. Therefore, as with all COMSOL products, the interfaces within the AC/DC Module can be combined with any other module to account for thermal, structural, and fluid interactions in your system.

AC/DC Module

The induction stove was designed to meet a consumer need for better precision and speed than traditional stoves. Designers were tasked with improving the energy efficiency of the induction coils-stovepot interaction considering both the thermal and electromagnetics of the system.
Miele, a world leader in domestic appliances and commercial ...

Transformers have been around for quite a while but their fundamentals are still being investigated by ABB in Ladenburgh, Germany. The ABB Corporate Research Centre is currently developing sophisticated magnetic sensors, using finite element analysis (FEA) to investigate the way in which external electrical sources and loads impact a magnetic ...

Consumers of power rely on fairly stable voltages. Transformers contain tap changers which vary the ratio of secondary to primary turns by switching the point at which either the input or output circuits are connected. Changing this ratio enables stepped voltage regulation of the output. As the world moves toward the modernized smart grid, the tap ...

Switching Made Easy

Matthias Richwin,
Leopold Kostal GmbH,
Dortmund, Germany

Modern cars offer a wide range of complex functionality that comes with several design challenges. This story discusses some of the necessary updates to a roof module in a premium car and the charging system of an electric car.
The roof module of a particular model houses several components. 90% of the generated heat goes into its printed circuit ...

How Reclosers Ensure a Steady Supply of Power: It’s All in the Magnet

O. Craciun, and colleagues
ABB AG
Ladenburgh, Germany

When a tree branch touches overhead cables and causes a momentary short circuit, your lights may flicker. A device called a recloser ensures that power to your home is not cut off for a longer period.
ABB AG, a leading manufacturer in power technology, is working towards designing a more reliable recloser. One objective in this design process was ...

Upgrading the Nuts and Bolts of the Electrical Grid for a New Generation

Migrating the electrical grid to a “smart grid” is usually discussed in terms of IT issues or embedded systems. Yet, just as important updating the “nuts and bolts” of the smart grid.
At ABB AB Corporate Research Power Technologies in Sweden, scientists are working to reduce line current and the resulting resistive loss in cables caused ...

Magnets Improve Quality of High-Power Laser Beam Welding

High-power laser beam welding uses a localized heat source to achieve narrow deep welds and high welding rates. Engineers run into some difficulties because the use of a localized heat source often results in the distortion of metal components; spattering and the ejection of droplets from the weld pool results in underfills, undercuts, craters, ...

Multiphysics Simulations Help Track Underground Fluid Movements

Combining acoustic and electromagnetic analyses helps scientists to more efficiently measure and survey subterranean regions. Acoustic waves can travel long distances, but have limitations when it comes to providing details about formation properties, and cannot be used to identify the liquids flowing through them. Electromagnetic waves do not ...

Simulation-Based Design of New Implantable Hearing Device

Patrik Kennes
Cochlear Technology Centre, Mechelen, Belgium

Cochlear Technology Centre Europe (CTCE) develops new technology for hearing implants. Their current work is with a new type of hearing implant, a Direct Acoustic Cochlear Implant called CodacsTM. This product imposes structural, pressure waves directly to the cochlea, stimulating it this way, as opposed to amplifying sound.
Using COMSOL ...

Control of Joule Heating Extends Performance and Device Life

Jean-Louis Gelet and Antoine Gerlaud
Mersen, France

Large electrical systems carrying high currents could pose a danger if any of their components, such as fuses and bus bars, fail. In order to increase safety and improve manufacturing, it is necessary to understand the failure mechanisms of those components. One of those components, a bus bar, is made up of a single piece of conducting metal that ...

Multiphysics Software, a Versatile, Cost-Effective R&D Tool at Sharp

Chris Brown
Sharp Laboratories of Europe, UK

There are several kinds of technology that designers at Sharp Laboratories of Europe work to create. From LED lighting, displays, and microfluidic lab-on-a-chip technology, to complex energy systems used in various devices, Sharp needed a new approach to finding the best designs. COMSOL Multiphysics and its add-on products provided the versatility ...

MRI Tumor-Tracked Cancer Treatment

Radiation therapy targeting in cancer treatment involves many uncertainties, including the movement of targeted sites due to breathing and the like. Magnetic resonance imaging (MRI) can accurately identify the location of a tumor in soft tissue, but unfortunately its magnetic field can interfere with radiation treatment delivered by a linear ...

Simulation of Magnetic Flux Leakage Inspection

Oliver Nemitz
Salzgitter Mannesmann Forschung, Duisburg, Germany

Salzgitter Mannesmann Forschung (SZMF) advances testing methods for the Salzgitter Group, a leading company that works with the manufacture of, among other things, pipes. In the manufacturing of heavy steel tubing, it is important maintain quality, which is done through conduct non-destructive testing (NDT) using large magnets to identify flaws ...

Modeling Scar Effects in Electrical Spinal Cord Stimulation

The Neuromodulation Group at Lahey Clinic conducted a study based upon spinal cord stimulation (SCS). SCS involves implanting a series of electrodes that apply electric potential to the spine, interfering with pain signaling circuitry. It’s used to alleviate chronic back and leg pain. Although the treatment remains effective for years, the ...

Reduced-Weight Reaction Sphere Makes Way for Extra Satellite Payload

Leopoldo Rossini, Emmanuel Onillon, & Olivier Chetelat

CSEM SA, Neuchatel, Switzerland

CSEM is a private applied research and development center specializing in micro-technology, system engineering, micro-electronics, and communications technologies. One of their latest projects is working on minimizing the weight of satellite attitude control systems as every gram of payload matters when launching a satellite into orbit (€15,000 ...

Reduced-Weight Reaction Sphere Makes Way for Extra Satellite Payload

The induction stove was designed to meet a consumer need for better precision and speed than traditional stoves. Designers were tasked with improving the energy efficiency of the induction coils-stovepot interaction considering both the thermal and electromagnetics of the system.
Miele, a world leader in domestic appliances and commercial ...

Transformers have been around for quite a while but their fundamentals are still being investigated by ABB in Ladenburgh, Germany. The ABB Corporate Research Centre is currently developing sophisticated magnetic sensors, using finite element analysis (FEA) to investigate the way in which external electrical sources and loads impact a magnetic ...

Consumers of power rely on fairly stable voltages. Transformers contain tap changers which vary the ratio of secondary to primary turns by switching the point at which either the input or output circuits are connected. Changing this ratio enables stepped voltage regulation of the output. As the world moves toward the modernized smart grid, the tap ...

Switching Made Easy

Matthias Richwin,
Leopold Kostal GmbH,
Dortmund, Germany

Modern cars offer a wide range of complex functionality that comes with several design challenges. This story discusses some of the necessary updates to a roof module in a premium car and the charging system of an electric car.
The roof module of a particular model houses several components. 90% of the generated heat goes into its printed circuit ...

How Reclosers Ensure a Steady Supply of Power: It’s All in the Magnet

O. Craciun, and colleagues
ABB AG
Ladenburgh, Germany

When a tree branch touches overhead cables and causes a momentary short circuit, your lights may flicker. A device called a recloser ensures that power to your home is not cut off for a longer period.
ABB AG, a leading manufacturer in power technology, is working towards designing a more reliable recloser. One objective in this design process was ...

Upgrading the Nuts and Bolts of the Electrical Grid for a New Generation

Migrating the electrical grid to a “smart grid” is usually discussed in terms of IT issues or embedded systems. Yet, just as important updating the “nuts and bolts” of the smart grid.
At ABB AB Corporate Research Power Technologies in Sweden, scientists are working to reduce line current and the resulting resistive loss in cables caused ...

Magnets Improve Quality of High-Power Laser Beam Welding

High-power laser beam welding uses a localized heat source to achieve narrow deep welds and high welding rates. Engineers run into some difficulties because the use of a localized heat source often results in the distortion of metal components; spattering and the ejection of droplets from the weld pool results in underfills, undercuts, craters, ...

Multiphysics Simulations Help Track Underground Fluid Movements

Combining acoustic and electromagnetic analyses helps scientists to more efficiently measure and survey subterranean regions. Acoustic waves can travel long distances, but have limitations when it comes to providing details about formation properties, and cannot be used to identify the liquids flowing through them. Electromagnetic waves do not ...

Simulation-Based Design of New Implantable Hearing Device

Patrik Kennes
Cochlear Technology Centre, Mechelen, Belgium

Cochlear Technology Centre Europe (CTCE) develops new technology for hearing implants. Their current work is with a new type of hearing implant, a Direct Acoustic Cochlear Implant called CodacsTM. This product imposes structural, pressure waves directly to the cochlea, stimulating it this way, as opposed to amplifying sound.
Using COMSOL ...

Control of Joule Heating Extends Performance and Device Life

Jean-Louis Gelet and Antoine Gerlaud
Mersen, France

Large electrical systems carrying high currents could pose a danger if any of their components, such as fuses and bus bars, fail. In order to increase safety and improve manufacturing, it is necessary to understand the failure mechanisms of those components. One of those components, a bus bar, is made up of a single piece of conducting metal that ...

Multiphysics Software, a Versatile, Cost-Effective R&D Tool at Sharp

Chris Brown
Sharp Laboratories of Europe, UK

There are several kinds of technology that designers at Sharp Laboratories of Europe work to create. From LED lighting, displays, and microfluidic lab-on-a-chip technology, to complex energy systems used in various devices, Sharp needed a new approach to finding the best designs. COMSOL Multiphysics and its add-on products provided the versatility ...

MRI Tumor-Tracked Cancer Treatment

Radiation therapy targeting in cancer treatment involves many uncertainties, including the movement of targeted sites due to breathing and the like. Magnetic resonance imaging (MRI) can accurately identify the location of a tumor in soft tissue, but unfortunately its magnetic field can interfere with radiation treatment delivered by a linear ...

Simulation of Magnetic Flux Leakage Inspection

Oliver Nemitz
Salzgitter Mannesmann Forschung, Duisburg, Germany

Salzgitter Mannesmann Forschung (SZMF) advances testing methods for the Salzgitter Group, a leading company that works with the manufacture of, among other things, pipes. In the manufacturing of heavy steel tubing, it is important maintain quality, which is done through conduct non-destructive testing (NDT) using large magnets to identify flaws ...

Modeling Scar Effects in Electrical Spinal Cord Stimulation

The Neuromodulation Group at Lahey Clinic conducted a study based upon spinal cord stimulation (SCS). SCS involves implanting a series of electrodes that apply electric potential to the spine, interfering with pain signaling circuitry. It’s used to alleviate chronic back and leg pain. Although the treatment remains effective for years, the ...

Reduced-Weight Reaction Sphere Makes Way for Extra Satellite Payload

CSEM is a private applied research and development center specializing in micro-technology, system engineering, micro-electronics, and communications technologies. One of their latest projects is working on minimizing the weight of satellite attitude control systems as every gram of payload matters when launching a satellite into orbit (€15,000 ...

AC/DC Module

Inductor in an Amplifier Circuit

This model shows how to combine an electric circuit simulation with a finite element simulation. The finite element model is an inductor with a nonlinear magnetic core and 1000 turns, where the number of turns is modeled using a distributed current technique.
The circuit is imported into COMSOL Multiphysics as a SPICE netlist, which merges the ...

Modeling of a 3D Inductor

Inductors are used in many applications for low pass filtering or for impedance matching of predominantly capacitive loads. They are used in a wide frequency range from near static up to several MHz. An inductor usually has a magnetic core to increase the inductance, while keeping its size small. The magnetic core also reduces the electromagnetic ...

E-Core Transformer

This is the transient model of a single phase E-core transformer using a Multi-Turn Coil Domain. The model includes the effect of a nonlinear B-H curve in the core and shows how to connect the transformer model to the external circuits using Electric Circuit interface. The simulation is performed for two different cases; the first one with a unity ...

Inductive Heating of Copper Cylinder

The induced currents in a copper cylinder produce heat that in turn change the electrical conductivity. This means that the field propagation has to be solved simultaneously with the heat transfer through the cylinder and surrounding system.
This model shows this coupling between eddy currents and heat transfer as a tutorial example.

Permanent Magnet

As an example of a magnetostatic problem, consider how to model a horseshoe-shaped permanent magnet. One way is to treat the entire magnet as a ferromagnetic material, where the two end sections are defined as being pre-magnetized in different and opposite directions. An alternative is to set surface currents on the pre-magnetized parts. In this ...

Mutual Inductance and Induced Currents in a Multi-Turn Coil

The mutual inductance and induced currents between a single turn primary and twenty turn secondary coil in a concentric coplanar arrangement is computed using a frequency domain model. The secondary coil is modeled using a homogenized approach which does not explicitly consider each turn of the coil. The results are compared against analytic ...

Transmission Line Parameter Calculator

The transmission line parameters R, L, G and C are used to characterize any TEM and quasi TEM waveguide structure. This application computes R, L, G and C as well as the characteristic impedance and propagation constant for some common types of transmission lines.

Electron Beam Diverging Due to Self Potential

When modeling the propagation of charged particle beams at high currents, the space charge force generated by the beam significantly affects the trajectories of the charged particles. Perturbations to these trajectories, in turn, affect the space charge distribution.
The Charged Particle Tracing interface can use an iterative procedure to ...

Tunable MEMS Capacitor

In an electrostatically tunable parallel plate capacitor, the distance between the two plates can be modified by a spring, as the applied voltage changes.
For a given voltage difference between the plates, the distance of the two plates can be computed, if the characteristics of the spring are known. Knowledge of this means that the distance ...

Inductive Heating of Copper Cylinder

Permanent Magnet

Mutual Inductance and Induced Currents in a Multi-Turn Coil

Transmission Line Parameter Calculator

Electron Beam Diverging Due to Self Potential

Tunable MEMS Capacitor

Inductor in an Amplifier Circuit

This model shows how to combine an electric circuit simulation with a finite element simulation. The finite element model is an inductor with a nonlinear magnetic core and 1000 turns, where the number of turns is modeled using a distributed current technique.
The circuit is imported into COMSOL Multiphysics as a SPICE netlist, which merges the ...

Modeling of a 3D Inductor

Inductors are used in many applications for low pass filtering or for impedance matching of predominantly capacitive loads. They are used in a wide frequency range from near static up to several MHz. An inductor usually has a magnetic core to increase the inductance, while keeping its size small. The magnetic core also reduces the electromagnetic ...

E-Core Transformer

This is the transient model of a single phase E-core transformer using a Multi-Turn Coil Domain. The model includes the effect of a nonlinear B-H curve in the core and shows how to connect the transformer model to the external circuits using Electric Circuit interface. The simulation is performed for two different cases; the first one with a unity ...

Inductive Heating of Copper Cylinder

The induced currents in a copper cylinder produce heat that in turn change the electrical conductivity. This means that the field propagation has to be solved simultaneously with the heat transfer through the cylinder and surrounding system.
This model shows this coupling between eddy currents and heat transfer as a tutorial example.

Permanent Magnet

As an example of a magnetostatic problem, consider how to model a horseshoe-shaped permanent magnet. One way is to treat the entire magnet as a ferromagnetic material, where the two end sections are defined as being pre-magnetized in different and opposite directions. An alternative is to set surface currents on the pre-magnetized parts. In this ...

Mutual Inductance and Induced Currents in a Multi-Turn Coil

The mutual inductance and induced currents between a single turn primary and twenty turn secondary coil in a concentric coplanar arrangement is computed using a frequency domain model. The secondary coil is modeled using a homogenized approach which does not explicitly consider each turn of the coil. The results are compared against analytic ...

Transmission Line Parameter Calculator

The transmission line parameters R, L, G and C are used to characterize any TEM and quasi TEM waveguide structure. This application computes R, L, G and C as well as the characteristic impedance and propagation constant for some common types of transmission lines.

Electron Beam Diverging Due to Self Potential

When modeling the propagation of charged particle beams at high currents, the space charge force generated by the beam significantly affects the trajectories of the charged particles. Perturbations to these trajectories, in turn, affect the space charge distribution.
The Charged Particle Tracing interface can use an iterative procedure to ...

Tunable MEMS Capacitor

In an electrostatically tunable parallel plate capacitor, the distance between the two plates can be modified by a spring, as the applied voltage changes.
For a given voltage difference between the plates, the distance of the two plates can be computed, if the characteristics of the spring are known. Knowledge of this means that the distance ...